In many electronics applications, an analog input signal is converted to a digital output signal (e.g., for further digital signal processing) using an analog-to-digital converter (ADC). Generally speaking, ADCs are electronic devices that convert a continuous physical quantity carried by an analog signal to a digital number that represents the quantity's amplitude (or to a digital signal carrying that digital number). ADCs can be found in many places such as broadband communication systems, audio systems, receiver systems, etc. For instance, in precision measurement systems, electronics are provided with one or more sensors to make measurements, and these sensors may generate an analog signal. The analog signal would then be provided to an ADC as input to generate a digital output signal for further processing. In another instance, an antenna generates an analog signal based on the electromagnetic waves carrying information/signals in the air. The analog signal generated by the antenna is then provided as input to an ADC to generate a digital output signal for further processing.
An ADC is typically composed of many electronic components making up an integrated circuit or a chip, and the ADC can be defined by the following application requirements: its speed, its bandwidth (the range of frequencies of analog signals it can properly convert to a digital signal), its resolution (the number of discrete levels the maximum analog signal can be divided into and represented in the digital signal), and its signal to noise ratio (how accurately the ADC can measure signal relative to the noise the ADC introduces), and so on. ADCs are used in a broad range of applications including communications, energy, healthcare, instrumentation and measurement, motor and power control, industrial automation and aerospace/defense. ADCs have many different designs, which can be chosen based on the application requirements. ADCs provide an essential functionality for electronics, and designing an ADC is a non-trivial task because each application may have different sets of requirements.